Be very very careful. You should make your views clear and be ready to argue for your own position, but the arrangement you have is, legally speaking, really quite weak. If you allow this to descend into a dispute, it may be something which will be very difficult to recover from.

The best argument is that a dispute will destroy the value of the flats. Who is going to pay properly to walk into an unresolved dispute. People may have no current intention of selling, but a dispute can have repercussions long into the future.

This often means swallowing a lot of pride, and taking many a deep breath before opening the mouth. The arrangement you have is one which ties each of you to the other very closely - think of it as a marriage with neither the affection nor any means of divorce.

I would ask myself if there is a do nothing option.. I think this might help understand the position of those who don't think its a priority. You could easily run up costs more than double the cost of the work.